At last week's Ecobuild show in London, he explained that the Romsey and North Baddesley masterplan, produced by the Prince's Foundation for the Built Environment in consultation with the SA, "will be built around the need to source staple foods from the area".

The SA is also involved in a study to establish to what degree Wales could become self-sufficient in food, he added.

"Two crucial questions of the 21st century will be resource depletion and population growth," he said. "We are heading for an energy crunch, and its sister is the food crunch. There could be dark times ahead unless we have a strategy to produce food as close as is practicable to where it's consumed."

Federation of City Farms and Community Gardens chief executive Jeremy Iles said he wanted private landowners and local authorities on board in order to increase land for growing. "Creating new sites is difficult," he said. "We are starting to get a warmer reception, but they need to know it's not neat and tidy, it's messy."

To those considering establishing sites for community gardening, he said: "Please don't reinvent the wheel. Come to us - we have 30 years of experience in doing this."

London Food chair Rosie Boycott said the Capital Growth plan to create 2012 community plots by 2012 was on course, saying: "We have 800 to 900 already committed and will have 1,000 by summer."

She admitted that "we nicked the idea from Vancouver's 2010 campaign," but pointed to other successful initiatives in Chicago and Stockholm."It brings communities together, even on tough estates," she said. "It works because it's not allotments - people like Transport for London would run a mile from that. Instead they give out a five-year lease."

Architect and author Carolyn Steel added: "In the past, cities were supplied by market gardens, while 'night soils' went the other way. We can reinterpret old models of how cities fed themselves."